"""阿里云百炼背景图生成服务。"""

from __future__ import annotations

import logging
from pathlib import Path
from typing import Any

import httpx

from app.core.config import get_settings
from app.core.errors import DependencyUnavailableError, UpstreamTimeoutError
from app.service.model_gateway import EnvironmentSecretResolver

logger = logging.getLogger(__name__)


class PromotionImageService:
    """生成无文字底图，供渲染器美化整页与内容面板。"""

    def __init__(self) -> None:
        settings = get_settings()
        self.enabled = settings.promotion_image_enabled
        self.api_key = ""
        if self.enabled:
            try:
                self.api_key = EnvironmentSecretResolver().resolve(
                    "env:DASHSCOPE_API_KEY"
                )
            except Exception:
                logger.warning("DASHSCOPE_API_KEY 未配置，背景图生成已降级", exc_info=True)
                self.enabled = False
        self.base_url = settings.promotion_image_base_url.rstrip("/")
        self.model = settings.promotion_image_model
        self.timeout_seconds = settings.promotion_image_timeout_seconds
        self.poll_interval_seconds = settings.promotion_image_poll_interval_seconds

    async def generate_background(
        self,
        *,
        output_path: str | Path,
        style_code: str,
        background_theme: str,
        fund_type: str,
    ) -> str | None:
        if not self.enabled or not self.api_key:
            return None
        prompt = self._build_prompt(
            style_code=style_code,
            background_theme=background_theme,
            fund_type=fund_type,
        )
        try:
            async with httpx.AsyncClient() as client:
                task_id = await self._submit(client, prompt)
                image_url = await self._poll(client, task_id)
                response = await client.get(
                    image_url,
                    timeout=httpx.Timeout(self.timeout_seconds),
                )
                response.raise_for_status()
                destination = Path(output_path)
                destination.parent.mkdir(parents=True, exist_ok=True)
                destination.write_bytes(self._tone_down_background(response.content))
                return str(destination)
        except httpx.TimeoutException:
            logger.warning("阿里云背景图生成超时，使用程序化背景", exc_info=True)
            return None
        except (
            httpx.HTTPError,
            DependencyUnavailableError,
            UpstreamTimeoutError,
            KeyError,
            TypeError,
            ValueError,
        ):
            logger.warning("阿里云背景图生成失败，使用程序化背景", exc_info=True)
            return None

    async def _submit(self, client: httpx.AsyncClient, prompt: str) -> str:
        response = await client.post(
            f"{self.base_url}/api/v1/services/aigc/text2image/image-synthesis",
            headers={
                "Authorization": f"Bearer {self.api_key}",
                "Content-Type": "application/json",
                "X-DashScope-Async": "enable",
            },
            json={
                "model": self.model,
                "input": {"prompt": prompt},
                "parameters": {"size": "1024*1024", "n": 1},
            },
            timeout=httpx.Timeout(self.timeout_seconds),
        )
        response.raise_for_status()
        body: Any = response.json()
        task_id = body.get("output", {}).get("task_id") if isinstance(body, dict) else None
        if not isinstance(task_id, str) or not task_id:
            raise DependencyUnavailableError("阿里云背景图任务响应缺少 task_id")
        return task_id

    async def _poll(self, client: httpx.AsyncClient, task_id: str) -> str:
        url = f"{self.base_url}/api/v1/tasks/{task_id}"
        max_polls = max(1, int(self.timeout_seconds / self.poll_interval_seconds))
        for _ in range(max_polls):
            response = await client.get(
                url,
                headers={"Authorization": f"Bearer {self.api_key}"},
                timeout=httpx.Timeout(self.timeout_seconds),
            )
            response.raise_for_status()
            body: Any = response.json()
            output = body.get("output", {}) if isinstance(body, dict) else {}
            status = output.get("task_status")
            if status == "SUCCEEDED":
                results = output.get("results") or []
                image_url = results[0].get("url") if results else None
                if isinstance(image_url, str) and image_url:
                    return image_url
                raise DependencyUnavailableError("阿里云背景图任务缺少图片地址")
            if status in {"FAILED", "CANCELED", "UNKNOWN"}:
                raise DependencyUnavailableError("阿里云背景图任务未成功")
            await self._sleep()
        raise UpstreamTimeoutError("阿里云背景图任务轮询超时")

    async def _sleep(self) -> None:
        import asyncio

        await asyncio.sleep(self.poll_interval_seconds)

    @staticmethod
    def _tone_down_background(payload: bytes) -> bytes:
        """将模型背景处理成低干扰底图，避免纹理压过材料正文。"""
        import io

        from PIL import Image, ImageEnhance, ImageFilter

        with Image.open(io.BytesIO(payload)) as source:
            image = source.convert("RGB")
            image = ImageEnhance.Color(image).enhance(0.22)
            image = ImageEnhance.Contrast(image).enhance(0.30)
            image = ImageEnhance.Brightness(image).enhance(1.22)
            image = image.filter(ImageFilter.GaussianBlur(radius=1.0))
            output = io.BytesIO()
            image.save(output, format="PNG", optimize=True)
            return output.getvalue()

    @staticmethod
    def _build_prompt(
        *,
        style_code: str,
        background_theme: str,
        fund_type: str,
    ) -> str:
        style = {
            "steady_professional": "稳健、克制、专业的暖色金融视觉",
            "growth_research": "理性、现代、研究感的蓝色金融视觉",
            "balanced_allocation": "平衡、清晰、专业的蓝金金融视觉",
        }.get(style_code, "专业、克制、清晰的金融视觉")
        theme = {
            "data_lines": "抽象数据线、轻量节点和流动曲线",
            "geometric_grid": "低对比几何网格、细线和少量节点",
            "soft_wave": "柔和抽象波形和层次光影",
        }.get(background_theme, "低对比抽象几何纹理")
        return (
            "Use case: productivity-visual. "
            "为基金产品推介材料生成可作为 PPT 和宣传长图底图的抽象背景。"
            f"基金类型语境：{fund_type}。视觉风格：{style}。主要元素：{theme}。"
            "宽松留白，主体内容区域保持低对比，适合叠加中文文字和数据图表；"
            "画面主色应可用于提取同色系的半透明文字板块背景。"
            "只生成背景和装饰纹理，不生成任何文字、数字、字母、Logo、人物、头像、"
            "基金图表、表格、产品名称、收益率、金融承诺、印章或水印。"
        )